1. Technical Field
The present invention relates generally to wireless communication systems; and more particularly to a wireless communication system supporting cooperative selection of frequency bands, radio frequency (RF) channels, protocols and protocol revisions for subsequent communications between the network and subscribing units operating within a service area supported by the network. Further, the present invention relates to a wireless communication system in which the necessary system operating information is contained within the broadcast messages, such operating information used in the selection of the mode of operation (Digital or Analog) and the selection of the frequency band in which the wireless communication services are provided.
2. Related Art
Wireless communication systems are well known in the art. Such systems facilitate communication between a user of a wireless subscribing unit and users of other wireless subscribing units as well as between wireless subscribing units and users of wired units, such as those attached to the public switched telephone network. Depending upon the particular implementation, wireless communication systems may operate according to multiple protocols in particular frequency bands and on particular channels contained within the frequency bands. Frequency bands currently in use in North America and around the world for wireless communications include the 800 MHz (cellular) band and the 1900 MHz (PCS) band among others.
Various communication protocols have been developed to standardize different wireless communication technologies. These communication protocols include, for example, the Advanced Mobile Phone Service (AMPS) standards, the Narrowband Advanced Mobile Phone Service (NAMPS) standards, the Global Standard for Mobility (GSM), the Code Division Multiple Access (CDMA) standards and the Time Division Multiple Access (TDMA) standards among others. Further, these standardized protocols typically include various protocol revisions that must be accommodated, the protocol revisions further defining how additional wireless communication services and features are supported.
In most installations, a plurality of base stations managed by a mobile switching center (MSC) support wireless communications within a particular geographic area. Together, these components are referred to as a "network" and provide wireless coverage within a service area. Typically, separate service providers maintain their own service areas which may overlap one another, each service provider maintaining a network to support its wireless service. Large geographic areas, often referred to as metropolitan trading areas (MTA), are typically serviced by multiple service providers. To maximize revenues, each service provider desires to serve a maximum number of subscribing units within the MTA. Presently, such may only be accomplished by having each user subscribe to a particular service provider.
With the advent of multiple communication protocols and technologies, in an effort to serve more subscribing units, service providers may provide wireless service in multiple frequency bands and according to multiple communication protocols. For example, the service provider may support both AMPS standards and CDMA standards on the cellular band while supporting only CDMA standards on the PCS band. While such multiple offerings may increase the potential number of subscribing units that may be served, the coordination between various communication protocols and various frequency bands within the system is required. However, the mechanism by which the system can coordinate this complex operation is not specified in the current standards. Further, because of the relative expense of supporting the multiple frequency bands and the multiple communication protocols, most service providers are limited to providing services for less than the full possible offering sets.
Manufacturers of subscribing units have responded to multiple service offerings by producing subscribing units that operate across multiple frequency bands and according to multiple protocols. For example, a multiple mode subscribing unit may support both operation under the analog AMPS (e.g., EIA/TIA-553, IS-91A) standard and operation under the digital CDMA (e.g., IS-95, IS-95B) standard which operates in multiple frequency bands. Further, in other situations, the subscribing units may operate under both AMPS (e.g., EIA/TIA-553) standard and the TDMA (e.g., IS-136) standard which operates in multiple frequency bands. However, coordinating operation for the subscribing unit in the multiple frequency bands and according to multiple protocols has proven difficult. Since the multiple mode subscribing units operating according to analog standards in multiple mode systems typically do not indicate the capability of the network, identifying operating capabilities, much less choosing from the available operating capabilities, has been difficult if not impossible.
As the number of subscribers operating within a particular service area increases, traffic within the service area also increases. Oftentimes, access and traffic channels are not available when requested and subscribers cannot access the system when desired. To compound problems, most subscribing units operate according to older analog protocols. Thus, even when sufficient bandwidth is available on the PCS bands to support communication for all multiple mode digital (CDMA) subscribing units in a certain service area, traffic problems may still exist. Further, due to shortcomings in the operation of subscribing units that can operate in both the AMPS standard and the CDMA standard, the subscribing units often fail to move to the less trafficked CDMA frequency bands due to lack of system information on the broadcast signal and lack of communication facilities between the subscribing units and the base station.
Thus, there exists a need in the art for a wireless communication system that efficiently causes subscribing units to operate among the various available frequency bands and protocols and to allow the subscribing units to request additional information from the AMPs networks regarding these frequency bands.